Mark PSBTs spending unspendable outputs as invalid in analysis

src/node/psbt.cpp

@@ -7,6 +7,7 @@
 #include <node/psbt.h>
 #include <policy/policy.h>
 #include <policy/settings.h>
+#include <tinyformat.h>
 
 #include <numeric>
 
@@ -39,6 +40,11 @@ PSBTAnalysis AnalyzePSBT(PartiallySignedTransaction psbtx)
             calc_fee = false;
         }
 
+        if (!utxo.IsNull() && utxo.scriptPubKey.IsUnspendable()) {
+            result.SetInvalid(strprintf("PSBT is not valid. Input %u spends unspendable output", i));
+            return result;
+        }
+
         // Check if it is final
         if (!utxo.IsNull() && !PSBTInputSigned(input)) {
             input_analysis.is_final = false;